Test systems are used to test products that have been manufactured in order to determine if the product is working to the product's design specifications. Products that are tested with such test systems include electronic devices, such as logic devices (also referred to as chips) with package-on-package (POP) structures. Such POP structures typically comprise an electronic device like a logic device that that has surface mount packaging like a Ball Grid Array (BGA). The BGA are solder balls on a surface or surfaces of the logic device. These BGA balls allow mounting of a second device such as a memory device directly on top of the logic device instead of having to rely on a circuit board and traces to interconnect the logic device to the memory, thus saving precious circuit board space and thereby lower the cost. Some types of logic devices that are tested can include processors, mobile station modems as used in mobile phones, radio frequency circuits, digital and analog devices and any other type of electronic chip that can take advantage of vertical stacking provided by POP structures.
Current automated system level test systems that perform system level test of logic devices that include a temporarily interconnected POP device such as a POP memory typically involve two handler arms which are required for the testing. One handler arm inserts the logic device onto a testing socket and the second handler arm places the memory directly on top of the device, making sure the memory is properly aligned and making proper electrical interconnection to the logic device. An alternative to the two handler arm technique is to use a single handler arm containing the memory and vacuum provided on the sides of the memory to pick and place the base logic device and place it into a testing socket. Both of the above test systems describe test system architectures that do not scale very well and cannot test a high volume of devices in a timely or cost effective fashion. This causes the test times to be too long, thus increasing the cost of the testing of each device.